/Engine/Source/Runtime/Core/Public/IO/IoDispatcher.h
Chunks providedMUSTdecompress to bits that hash to the exact value provided in InChunkKey (i.e. be exactly the same bits), and also be the same number of blocks (i.e. same CompressionBlockSize)
bool RetrieveChunk ( const TPair< [FIoContainerId](API\Runtime\Core\IO\FIoContainerId), [FIoChunkHash](API\Runtime\Core\IO\FIoChunkHash) > & InChunkKey, [TUniqueFunction](API\Runtime\Core\Templates\TUniqueFunction)< void([TIoStatusOr](API\Runtime\Core\IO\TIoStatusOr)< [FIoStoreCompressedReadResult](API\Runtime\Core\IO\FIoStoreCompressedReadResult) >)> InCompletionCallback )